Accelerated organoborane amine complex initiated polymerizable compositions

ABSTRACT

The invention is a two part polymerizable composition comprising in one part an organoboron compound capable of forming free radical generating species amine complex and in the second part one or more compounds capable of free radical polymerization and a cure accelerator comprising a) at least one compound containing a quinone structure or b) at least one compound containing at least one aromatic ring and one or more, preferably two substituents on the aromatic ring selected from hydroxyl, ether and both, where there are two substituents they are located either ortho or para with respect to one another and a peroxide containing compound. The second part may further contain an agent capable of causing the organoboron compound to form free radical generating species upon contacting the two parts. The first part may further comprises one or more compounds capable of free radical polymerization. This facilitates formulating compositions that have commercially desirable volumetric ratios of the two parts. Adhesive compositions of the present formulation provide excellent adhesion to low surface energy substrates, such as plastics.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of prior application Ser. No.11/019,056, filed Dec. 21, 2004. This application claims the benefit ofU.S. Provisional Application No. 60/532,066, filed Dec. 22, 2003.

BACKGROUND OF THE INVENTION

This invention relates to accelerated polymerizable compositionscomprising compounds containing moieties capable of free radicalpolymerization, organoboron compounds capable of forming free radicalgenerating species capable of initiating free radical polymerization andadhesives based on such compositions. In another embodiment theinvention relates to a method of polymerizing compounds containingmoieties capable of free radical polymerization and to methods ofbonding substrates using such compositions.

Low surface energy olefins such as polyethylene, polypropylene andpolytetrafluoroethylene have a variety of attractive properties in avariety of uses, such as toys, automobile parts, furniture applicationsand the like. Because of the low surface energy of these plasticmaterials, it is very difficult to find adhesive compositions that bondto these materials. The commercially available adhesives that are usedfor these plastics require time consuming or extensive pretreatment ofthe surface before the adhesive will bond to the surface. Suchpretreatments include corona treatment, flame treatment, the applicationof primers, and the like. The requirement for extensive pretreatment ofthe surface results in significant limitations to the designers ofautomobile components, toys, furniture and the like.

A series of patents issued to Skoultchi, U.S. Pat. Nos. 5,106,928;5,143,884; 5,286,821; 5,310,835 and 5,376,746 (all incorporated hereinby reference) and to Zharov, et al., U.S. Pat. Nos. 5,539,070;5,690,780; and 5,691,065 (all incorporated herein by reference) disclosepolymerizable acrylic compositions which are particularly useful asadhesives wherein organoboron amine complexes are used to initiate cure.It is disclosed that these complexes are good for initiatingpolymerization of an adhesive that bonds to low surface energysubstrates. Pocius in a series of patents, U.S. Pat. No. 5,616,796; U.S.Pat. No. 5,621,143; U.S. Pat. No. 5,681,910; U.S. Pat. No. 5,686,544;U.S. Pat. No. 5,718,977; and U.S. Pat. No. 5,795,657 (all incorporatedherein by reference) disclose amine organoboron complexes with a varietyof amines used to complex the organoboron such as polyoxyalkylenepolyamines and polyamines which are the reaction product of diprimaryamines and compound having at least two groups which react with aprimary amine.

A series of patents by Sonnenschein et al. U.S. Pat. Nos. 6,806,330;6,730,759; 6,706,831; 6,713,578; 6,713,579 and 6,710,145, disclose amineorganoboron complexes wherein the organoboron is a trialkyl borane andthe amine is selected from the group of amines having an amidinestructural component; aliphatic heterocycles having at least onenitrogen in the heterocyclic ring; an alicyclic compound having bound tothe ring a substituent having an amine moiety; primary amines which inaddition have one or more hydrogen bond accepting groups wherein thereare at least two carbon atoms, preferably at least three carbon atoms,between the primary amine and the hydrogen bond accepting group; andconjugated imines. These patent applications disclose polymerizablecompositions containing the amine organoboron complexes one or more ofmonomers, oligomers or polymers having olefinic unsaturation which arecapable of polymerization by free radical polymerization and that thepolymerizable compositions can be used as adhesive, sealant, coating orink compositions.

Some of the references discussed above disclose the use of phenoliccompounds, such as hydroquinones to stabilize the compositions againstundesired polymerization. See Pocius, U.S. Pat. No. 5,684,102 at column18, lines 45-53; Pocius, U.S. Pat. No. 5,861,910 at column 13 lines 17to 24. Jennes, U.S. Pat. No. 3,236,823 discloses the use ofhydroquinones, phenathiazine or t-butyl pyrocatechol as stabilizers inalkylborane initiated acrylate systems. Many of the disclosedcompositions polymerize more slowly than is desired for use inindustrial processes. This results in processes which exhibit lowproductivity.

Therefore, there is a need for adhesive systems that are capable ofbonding to low surface energy substrates, and initiator systems whichfacilitate such bonding. What are further needed are polymercompositions and adhesive systems which are thermally stable at, ornear, ambient temperatures and which will undergo polymerization whenthe user desires. Also needed are adhesive compositions which arecapable of bonding to low surface energy substrates, and bonding lowsurface energy substrates to other substrates, without the need forextensive or costly pretreatment. Further compositions that can be usedin existing commercial equipment at mix ratios of 4:1 or less areneeded. Compositions that have stability, strength and adhesion atelevated temperatures are also desired. Further needed are compositionswhich cure rapidly as many industrial processes require fast cycletimes.

SUMMARY OF INVENTION

The invention is a two part polymerizable composition comprising in onepart an organoboron compound capable of forming free radical generatingspecies amine complex and in the second part one or more compoundscapable of free radical polymerization and a cure accelerator comprisinga) at least one compound containing a quinone structure or b) at leastone compound containing at least one aromatic ring and one or more,preferably two substituents, on the aromatic ring selected fromhydroxyl, ether and both. Where there are two substituents they arelocated either ortho or para with respect to one another and a peroxidecontaining compound. The second part may further contain an agentcapable of causing the organoboron compound to form free radicalgenerating species upon contacting the two parts. The first part mayfurther comprise one or more compounds capable of free radicalpolymerization. This facilitates formulating compositions that havecommercially desirable volumetric ratios of the two parts. Adhesivecompositions of the present formulation provide excellent adhesion tolow surface energy substrates, such as plastics.

The invention is also a method of polymerization comprising contactingthe components of the polymerizable composition under conditions suchthat the polymerizable compounds undergo polymerization. In oneembodiment, the contacting occurs at, or near, ambient temperature. Inanother embodiment, the method further comprises the step of heating thepolymerized composition to an elevated temperature under conditions suchthat the organoboron compound forms a free radical generating species.

In yet another embodiment the invention is a method of bonding two ormore substrates together which comprises contacting the components ofthe polymerizable composition together under conditions, such thatpolymerization is initiated; contacting the polymerizable compositionwith the two or more substrates; positioning the two or more substrates,such that the polymerizable composition is located between the two ormore substrates; and allowing the polymerizable composition topolymerize and to bond the two or more substrates together. In yetanother embodiment the invention is a method of coating a substratewhich comprises contacting a composition according to the invention withone or more surfaces of a substrate and initiating polymerization of thecomposition according to the invention. In another embodiment theinvention is a laminate comprising two substrates having disposedbetween the substrates and bound to each substrate a compositionaccording to the invention.

The polymerizable compositions of the invention are stable at, or near,ambient temperature and can be cured upon demand by contacting the twoparts of the composition, or alternatively by contacting the two partsof the composition and thereafter heating the compositions above thetemperature at which the organoboron compound forms a free radicalgenerating species. Furthermore, the polymerizable compositions of theinvention can form good bonds to low surface energy substrates withoutthe need for primers or surface treatment. The polymerizablecompositions of the invention may be formulated to be dispensed incommercial equipment at volume ratios of the two parts of 4:1 or less.The polymerized compositions demonstrate excellent cohesive and adhesivestrength at elevated temperatures and thus demonstrate excellentstability at high temperatures. The polymerizable compositions of theinvention exhibit rapid cure and preferably exhibit a lap shear strengthaccording to ASTM 03165-91 of 50 psi or greater 1 hour afterapplication. Preferably, the polymerizable compositions demonstrateexcellent adhesion to substrates along with the rapid cure as discussed.

DETAILED DESCRIPTION OF THE INVENTION

The polymerization initiator is an organoboron containing compound whichis capable of forming a trivalent organoboron compound. In a preferredembodiment, the free radical generating species is a trivalentorganoboron compound free radical generating species. Preferred boroncontaining compounds are tetravalent in that they have four bonds to theboron of which at least three are covalent and one may be covalent or inthe form of an electronic association with a complexing agent. The freeradical generating species, such as a trivalent boron compound, isformed when the boron containing compound is contacted with anothersubstance, referred to herein as a decomplexing agent or initiator. Thefree radical generating species generates free radicals by reacting withenvironmental oxygen. In the embodiment wherein the boron containingcompound is tetravalent such contacting causes the abstraction of one ofthe ligands bonded to or complexed to the boron atom to convert it to atrivalent borane. Free radical generating species is a compound thatcontains or generates free radicals under polymerization conditions. Thedecomplexing agent or initiator can be any compound which reacts withthe complexing agent or which abstracts a cation from the boroncontaining compound. Preferably, the boron containing compound is anorganoborate or an organoboron amine complex.

An organoborate is a salt of a positive cation and an anionictetravalent boron. Any organoborate which can be converted to anorganoboron by contact with a decomplexing agent or initiator may beused. One class of preferred organoborates, (also known as quaternaryboron salts) are disclosed in Kneafsey et al., U.S. 2003/0226472 andKneafsey et al., U.S. 2004/0068067, both incorporated herein byreference. Preferred organoborates disclosed in these two U.S. patentapplications are described by the following formula

whereinR² is C₁-C₁₀ alkyl;R³ is independently in each occurrence C₁-C₁₀ alkyl, C₃-C₁₀ cycloalkyl,phenyl, phenyl-substituted C₁-C₁₀ alkyl or phenyl substituted C₃-C₁₀cycloalkyl, provided that any two of R² and/or R³ may optionally be partof a carbocyclic ring; andM⁺ is a metal ion or a quaternary ammonium ion. Preferred examples oforganoborates include sodium tetraethyl borate, lithium tetraethylborate, lithium phenyl triethyl borate and tetramethylammonium phenyltriethyl borate.

In another embodiment, the organoborate is an internally blocked borateas disclosed in Kendall et al., U.S. Pat. No. 6,630,555, incorporatedherein by reference. Disclosed in this patent are four coordinateinternally blocked borates wherein the boron atom is part of a ringstructure further containing an oxa or thio-moiety. The internallyblocked heterocyclic borates preferably have the following structure:

wherein J is oxygen or sulfur; when J represents oxygen, n is theinteger 2, 3, 4 or 5; when J represents sulfur, n is the integer 1, 2,3, 4 or 5; R⁴, R⁵, R⁶ and R⁷ are independently, substituted orunsubstituted alkyl or alkylene groups containing 1 to 10 carbon atoms,substituted aryl groups having up to 7 to 12 carbon atoms orunsubstituted aryl groups; R⁵, R⁶ and R⁷ can be hydrogen; R⁴ can be partof a second unsubstituted or substituted cyclic borate; R⁴ can comprisea spiro ring or a spiro-ether ring; R⁴ together with R⁵ can be linked toform a cycloaliphatic ring; or R⁴ together with R⁵ can comprise a cyclicether ring and M is any positively charged species; with m being anumber greater than 0.

The term “internally blocked” in reference to the organoboratesdescribed herein means a four coordinate boron atom being part of aninternal ring structure bridged across two of the four boron coordinatesor valences. Internal blocking includes a single ring or a multi-ringstructure where boron is part of one or multi-ring structures.

In the embodiment where the organoboron compound is in the form of anamine complex, the free radical generating species used in the inventionis a trialkyl borane or an alkyl cycloalkyl borane. The organoboron usedin the complex is a trialkyl borane or an alkyl cycloalkyl borane.Preferably such borane corresponds to the Formula:B—(—R¹)₃wherein B represents Boron; and R¹ is separately in each occurrence aC₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, or two or more of R¹ may combine to forma cycloaliphatic ring. Preferably R¹ is C₁₋₄ alkyl, even more preferablyC₂₋₄ alkyl, and most preferably C₃₋₄ alkyl. Among preferred organoboronsare tri-ethyl borane, tri-isopropyl borane and tri-n-butylborane.

In the embodiment wherein the organoboron compound is an organoboronamine complex, the organoboron is a trivalent organoboron and the aminecan be any amine which complexes reversibly with the organoboron. Suchcomplexes are represented by the formulaB—(—R¹)₃—A_(m)wherein R¹ is described hereinbefore and Am is an amine.

The amines used to complex the organoboron compound can be any amine ormixture of amines which complex the organoboron and which can bedecomplexed when exposed to a decomplexing agent. The desirability ofthe use of a given amine in an amine/organoboron complex can becalculated from the energy difference between the Lewis acid-basecomplex and the sum of energies of the isolated Lewis acid (organoboron)and base (amine) known as binding energy. The more negative the bindingenergy the more stable the complex.Binding Energy=−(Complex Energy−(Energy of Lewis Acid+Energy of Lewisbase))

Such binding energies can be calculated using theoretical ab-initiomethods such as the Hartree Fock method and the 3-21G basis set. Thesecomputational methods are available commercially employing commercialsoftware and hardware such as SPARTAN and Gaussian 98 programs with aSilicon Graphics workstation. Amines having amine/organoboron bindingenergies of 10 kilocalories per mol or greater are preferred, amineshaving a binding energy of 15 kilocalories per mol or greater are morepreferred and even more preferred are amines with a binding 20kilocalories per mol or greater are most preferred. In the embodimentwhere polymerization of the compositions of the invention is initiatedby use of a decomplexing agent the binding energy of the amine to theorganoboron is preferably about 50 kcal/mole or less and most preferablyabout 30 kcal/mole or less. In the embodiment where polymerization ofthe compositions of the invention is initiated by use of heat, thebinding energy of the amine is preferably about 100 kcal/mole or less,more preferably about 80 kcal/mole or less and most preferably about 50kcal/mole or less.

Preferred amines include the primary or secondary amines or polyaminescontaining primary or secondary amine groups, or ammonia as disclosed inZharov, U.S. Pat. No. 5,539,070 at column 5, lines 41 to 53,incorporated herein by reference, Skoultchi, U.S. Pat. No. 5,106,928 atcolumn 2, line 29 to 58, incorporated herein by reference, and Pocius,U.S. Pat. No. 5,686,544 at column 7, line 29 to column 10 line 36,incorporated herein by reference; ethanolamine, secondary dialkyldiamines or polyoxyalkylenepolyamines; and amine terminated reactionproducts of diamines and compounds having two or more groups reactivewith amines as disclosed in Deviny, U.S. Pat. No. 5,883,208 at column 7,line 30 to column 8 line 56, incorporated herein by reference. Withrespect to the reaction products described in Deviny the preferreddiprimary amines include alkyl diprimary amines, aryl diprimary amines,alkyaryl diprimary amines and polyoxyalkylene diamines; and compoundsreactive with amines include compounds which contain two or moremoieties of carboxylic acids, carboxylic acid esters, carboxylic acidhalides, aldehydes, epoxides, alcohols and acrylate groups. Preferredamines described in Deviny include n-octylamine, 1,6-diaminohexane(1,6-hexane diamine), diethylamine, dibutyl amine, diethylene triamine,dipropylene diamine, 1,3-propylene diamine(1,3-propane diamine),1,2-propylene diamine, 1,2-ethane diamine, 1,5-pentane diamine,1,12-dodecanediamine, 2-methyl-1,5-pentane diamine, 3-methyl-1,5-pentanediamine, triethylene tetraamine, diethylene triamine. Preferredpolyoxyalkylene polyamines include polyethyleneoxide diamines,polypropyleneoxide diamines, triethylene glycol propylene diamine,polytetramethyleneoxide diamine andpolyethyleneoxidecopolypropyleneoxide diamines.

In one preferred embodiment, the amine comprises a compound having aprimary amine and one or more hydrogen bond accepting groups, whereinthere are at least two carbon atoms, preferably at least about three,between the primary amine and hydrogen bond accepting groups.Preferably, an alkylene moiety is located between the primary amine andthe hydrogen bond accepting group. Hydrogen bond accepting group meansherein a functional group that through either inter- or intramolecularinteraction with a hydrogen of the borane-complexing amine increases theelectron density of the nitrogen of the amine group complexing with theborane. Preferred hydrogen bond accepting groups include primary amines,secondary amines, tertiary amines, ethers, halogen, polyethers,thioethers and polyamines. Preferred compounds having a primary amineand one or more hydrogen bond accepting groups are described inSonnenschein et al., U.S. Pat. No. 6,730,759, (column 4, line 60 tocolumn 5, line 67); U.S. Pat. Nos. 6,706,831; 6,713,578; 6,713,579 and6,710,145 relevant portions, incorporated herein by reference.

In another embodiment the amine is an aliphatic heterocycle having atleast one nitrogen in the heterocycle. The heterocyclic compound mayalso contain one or more of nitrogen, oxygen, sulfur or double bonds. Inaddition, the heterocycle may comprise multiple rings wherein at leastone of the rings has nitrogen in the ring. Preferable aliphaticheterocyclic amines are described in Sonnenschein et al., U.S. Pat. No.6,730,759 (column 6, lines 1 to 45); U.S. Pat. Nos. 6,706,831;6,713,578; 6,713,579 and 6,710,145 relevant portions, incorporatedherein by reference.

In yet another embodiment, the amine which is complexed with theorganoboron is an amidine. Any compound with amidine structure whereinthe amidine has sufficient binding energy as described hereinbefore withthe organoboron, may be used. Preferred amidine compounds are describedin Sonnenschein et al., U.S. Pat. No. 6,730,759, (column 6, line 4 tocolumn 7, line 21); U.S. Pat. Nos. 6,706,831; 6,713,578; 6,713,579 and6,710,145 relevant portions, incorporated herein by reference.

In yet another embodiment, the amine that is complexed with theorganoboron is a conjugated imine. Any compound with a conjugated iminestructure, wherein the imine has sufficient binding energy as describedhereinbefore with the organoboron, may be used. The conjugated imine canbe a straight or branched chain imine or a cylic imine. Preferred iminecompounds are described in Sonnenschein et al., U.S. Pat. No. 6,730,759(column 7, line 22 to column 8, line 24); U.S. Pat. Nos. 6,706,831;6,713,578; 6,713,579 and 6,710,145 relevant portions, incorporatedherein by reference.

In another embodiment the amine can be an alicyclic compound havingbound to the alicyclic ring a substituent containing an amine moiety.The amine containing alicyclic compound may have a second substituentthat contains one or more nitrogen, oxygen, sulfur atoms or a doublebond. The alicyclic ring can contain one or two double bonds. Thealicyclic compound may be a single or multiple ring structure.Preferably the amine on the first substituent is primary or secondary.Preferably the alicyclic ring is a 5 or 6 membered ring. Preferablyfunctional groups on the second substituent are amines, ethers,thioethers or halogens. Preferred alicyclic compound with one or moreamines containing substituents Sonnenschein et al., U.S. Pat. No.6,730,759 (column 8, line 25 to line 59); U.S. Pat. Nos. 6,706,831;6,713,578; 6,713,579 and 6,710,145 relevant portions, incorporatedherein by reference.

In another preferred embodiment the amine further contains siloxane,that is an amino siloxane. Any compound with both amine and siloxaneunits wherein the amine has sufficient binding energy as describedhereinbefore with the organoboron, may be used. Preferred amines withsiloxane moieties are further described in U.S. Pat. No. 6,777,512, andtitled AMINE ORGANOBORANE COMPLEX INITIATED POLYMERIZABLE COMPOSITIONSCONTAINING SILOXANE POLYMERIZABLE COMPONENTS, (column 10, line 14 tocolumn 11, line 29, incorporated herein by reference.

In the embodiment where the organoboron compound is an organoboron aminecomplex, the equivalent ratio of amine compound(s) to borane compound inthe complex is relatively important. An excess of amine is preferred toenhance the stability of the complex and in the embodiment where thedecomplexing agent is an isocyanate functional compound to react withthe isocyanate functional compound thereby resulting in the presence ofpolyurea in the final product. The presence of polyurea improves thehigh temperature properties of the composition.

Compounds capable of free radical polymerization which may be used inthe polymerizable compositions of the invention include any monomers,oligomers, polymers or mixtures thereof which contain olefinicunsaturation which can polymerize by free radical polymerization. Suchcompounds are well known to those skilled in the art. Mottus, U.S. Pat.No. 3,275,611, provides a description of such compounds at column 2,line 46 to column 4, line 16, incorporated herein by reference.Preferred classes of compounds containing olefinic unsaturation areSonnenschein et al., U.S. Pat. No. 6,730,759 (column 9, line 7 to line54); U.S. Pat. Nos. 6,706,831; 6,713,578; 6,713,579 and 6,710,145relevant portions, incorporated herein by reference.

Examples of preferable acrylates and methacrylates are disclosed inSkoultchi, U.S. Pat. No. 5,286,821 at column 3, lines 50 to column 6,line 12, incorporated herein by reference and Pocius, U.S. Pat. No.5,681,910 at column 9, line 28 to column 12, line 25, incorporatedherein by reference. Also useful in these compositions are acrylatecrosslinkinking molecules including ethylene glycol dimethacrylate,ethylene glycol diacrylate, triethyleneglycol dimethacrylate, diethyleneglycol bismethacryloxy carbonate, polyethylene glycol diacrylate,tetraethylene glycol dimethacrylate, diglycerol diacrylate, diethyleneglycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropanetrimethacrylate, isobornylmethacrylate and tetrahydrofurfurylmethacrylate.

In the embodiment where the composition is used as an adhesive, acrylateand/or methacrylate based compounds are preferably used as the compoundscapable of free radical polymerization. The most preferred acrylate andmethacrylate compounds include methylmethacrylate, butylmethacrylate,2-ethylhexylmethacrylate, and cyclohexylmethylmethacrylate. Preferredamounts of compounds capable of free radical polymerization arepreferably about 10 percent by weight or greater based on the totalformulation weight, more preferably about 20 percent by weight orgreater and most preferably about 30 percent by weight or greater.Preferred amounts of compounds capable of free radical polymerizationare preferably about 90 percent by weight or less based on the totalformulation weight, more preferably about 85 percent by weight or lessand most preferred 80 percent by weight or less.

The compositions of the invention include two part polymerizablecompositions comprising in one part an organoboron compound and one ormore compounds containing one or more ring opening heterocyclicmoieties, and in a second part, compounds capable of being polymerizedby free radical polymerization, a catalyst capable of polymerizingcompounds containing ring opening heterocyclic moieties a cureaccelerator of the invention and optionally a component that will causethe organoboron compound to form a free radical generating species. Inone embodiment the invention is a two phase system comprising a firstphase containing one or more polymers prepared from the compounds whichpolymerize by free radical polymerization and a second phase comprisingpolymerized or partially polymerized compounds derived from one or morecompounds containing ring opening heterocyclic moieties. In oneembodiment the polymer prepared from the compounds containingheterocyclic ring opening moieties is not miscible with the polymerprepared by free radical polymerization and thus the resultingpolymerized composition has at least two regions each rich in one of thetwo polymers formed. In one embodiment the two part compositionsinvention includes a polymerized portion comprising polymerized compoundcapable of free radical polymerization and a second portion comprisingunpolymerized or partially polymerized compounds having ring openingheterocyclic moieties. The two portions can be miscible, partiallymiscible or immiscible. In a preferred embodiment the polymerizedcomposition comprises two phases, one based on the compounds whichpolymerize through olefinic bonds and a second which polymerizes by aring opening reaction of a heterocyclic moiety. The cured compositionsof the invention preferably contain two regions that in many cases arenot miscible. In some embodiments the two regions are separate phases orare interpenetrating networks of two different polymers. The two regionscan be chemically bonded to one another if the composition includes acrosslinking compound.

The compound containing a heterocyclic ring opening moiety can be anymonomer, oligomer or prepolymer containing a heterocyclic moiety capableof ring opening and polymerization. The heteroatom in the heterocyclicmoiety is preferably nitrogen, oxygen or sulfur, with nitrogen andoxygen being preferred and oxygen being most preferred. Preferably theheterocyclic moiety is a 3 membered ring. Preferred heterocyclicmoieties are oxirane and aziridine moieties, with oxirane moieties beingmost preferred. Preferred heterocyclic ring opening compounds arefurther described in Sonnenschein et al., U.S. Pat. No. 6,762,260(column 10, line 34 to column 11, line 22), incorporated herein byreference.

The presence of the polymer derived from the heterocyclic ring openingpolymerizable compound, such as oxirane and aziridine, improves adhesionto higher surface energy plastics such as nylon, and also the thermalproperties of the polymerized or partially polymerized compositions ofthe invention. A sufficient amount of the heterocyclic ring openingcompound is used to improve the bonding to higher surface energysubstrates and to improve the high temperature properties of thepolymerized or partially polymerized composition. Thermal propertiesrefer herein to higher glass transition temperatures of the polymerizedcompositions and improved cohesive strength at elevated temperatures, asevidenced by higher lap shear strengths at elevated temperature, such as125 and 150° C. A significant improvement of glass transitiontemperature is 5° C. A significant improvement in lap shear strength isabout 50 psi or greater at 125° C. The total polymerizable formulationmay contain about 2 percent by weight of heterocyclic polymerizablecompound or greater; more preferably about 5 percent by weight orgreater and most preferred about 10 percent by weight or greater. Thepolymerizable formulation may contain about 50 percent by weight orless, more preferably about 45 percent by weight of less and mostpreferably about 40 percent by weight or less of heterocyclicpolymerizable compound.

In some cases it may be useful to crosslink the free radicalpolymerizable compound phase to the heterocyclic ring openingpolymerizable compound derived phase as described in Sonnenschein et al,U.S. Pat. No. 6,762,260 (column 11, line 53 to column 1, line 11),incorporated herein by reference. The amount of crosslinker used is thatamount which gives the desired properties, that is, sufficient lap shearstrength at 125° C. or above, yet does not cause the room temperatureadhesive strength to go below the desired value. Preferred amounts ofcrosslinker are about 0 percent by weight or greater based on the weightof the polymerizable formulation, more preferably about 1 percent byweight or greater; even more preferably about 3 percent by weight orgreater and most preferably about 5 percent by weight or greater.Preferably the amount of crosslinker used is about 20 percent by weightof the total polymerizable formulation or less; even more preferablyabout 15 percent by weight or less and most preferably about 12 percentby weight or less.

It is preferable that the heterocyclic ring opening polymerizablecompound polymerize at a similar rate as the polymerization rate of thecompounds containing moieties capable of free radical polymerization. Ifthe reaction of one polymerizable component is too slow, the compositionmay vitrify prior to obtaining acceptable conversion of monomer topolymer of both phases. The unreacted components can act as aplasticizer and degrade properties, such as adhesion, thermalperformance and the like. The properties of the final polymerizedcomposition may be enhanced by post heating the polymerized compositionto drive the completion of the polymerization of the heterocyclicpolymerizable compounds. This is performed by heating the polymerizedcomposition to a temperature above the glass transition temperature ofthe incompletely polymerized polymer(s). In this embodiment it ispreferred to post cure at the expected use temperature of the structure,more preferred at 5° C. above the expected use temperature of thecomposition and most preferred to provide a thermal post cure of 10° C.above the expected use temperature of the polymerized composition.Examples of post cure procedures are disclosed in Briggs (U.S. Pat. No.4,426,243) and Ersun-Hallsby, et al. (U.S. Pat. No. 5,204,386),incorporated herein by reference. A preferred embodiment of the ringopening polymerization of heterocyclic compounds is described inSonnenschein et al., U.S. Pat. No. 6,762,260 (column 12, line 24 to line65), incorporated herein by reference.

The organoboron compounds useful for polymerization of the compoundshaving moieties capable of free radical polymerization may be convertedto compounds capable of forming free radical generating species by theapplication of a decomplexation agent that will cause the formation ofcompounds capable of forming free radical generating species, such as atrivalent borane compound, such as by displacing the amine from theborane. The formation of compounds capable of forming the free radicalgenerating species such as, trivalent borane.

The displacement of the amine from the alkylborane can occur with anychemical for which the exchange energy is favorable, such as mineralacids, organic acids, Lewis acids, isocyanates, acid chlorides,sulphonyl chlorides, aldehydes, and the like. Preferred decomplexationagents are acids and isocyanates. In those embodiments where theinitiator for the ring opening polymerization is a Lewis acid, thedecomplexing agent may be omitted as Lewis acids may also function asthe decomplexing agent. If the Lewis acid is used as the decomplexingagent and heterocyclic ring opening polymerization initiator noadditional amounts are needed over those amounts needed to initiatepolymerization. The choice of initiator may be impacted by the use ofthe polymerizable composition. In particular, where the polymerizablecomposition is an adhesive and the material to which it will be bondedis polypropylene, the preferred class of initiators is isocyanateinitiators and where the substrate is nylon the preferred initiators areacids. Polymerization may also be initiated thermally. The temperatureat which the composition is heated to initiate polymerization isdictated by the binding energy of the complex. Generally the temperatureused to initiate the polymerization by decomplexing the complex is about30° C. or greater and preferably about 50° C. or greater. Preferably thetemperature at which thermally initiated polymerization is initiated isabout 120° C. or less and more preferably about 100° C. or less. Anyheat source that heats the composition to the desired temperature can beused, provided the heat source does not negatively impact the componentsof the composition or its function. In this manner the composition maybe contacted with the substrates either before or after the compositionis exposed to heat. If the composition is heated prior to contact withthe substrates, the composition should be contacted with the substratesbefore the composition has polymerized to the point at which thecomposition is no longer able to adhere to the substrates. It may benecessary in the thermally initiated reaction to control the oxygencontent such that there is adequate oxygen to create favorableconditions for radical formation but not so much as to inhibit thepolymerization.

In one embodiment the invention of the polymerizable compositions mayfurther comprise one or more compounds, oligomers or prepolymers havinga siloxane backbone and reactive moieties capable of polymerization acatalyst for the polymerization of the one or more compounds, oligomersor prepolymers having a siloxane backbone and reactive moieties capableof polymerization as disclosed in U.S. Pat. No. 6,777,512, titled AMINEORGANOBORANE COMPLEX INITIATED POLYMERIZABLE COMPOSITIONS CONTAININGSILOXANE POLYMERIZABLE COMPONENTS (column 12, line 66 to column 15, line54), incorporated herein by reference.

The compositions of the invention may further contain a stabilizingamount of a dihydrocarbyl hydroxylamine. Stabilizing as used hereinrefers to preventing polymerization until desired. Generally this meansthat polymerization is inhibited under normal storage conditions. Normalstorage conditions mean storage at a temperature of about 0° C. to about40° C., wherein the adhesive is stored in a sealed container. A stablecomposition is one that does not experience undesired viscosity growthduring a defined period. Viscosity growth is evidence of polymerizationof the monomers present. In a preferred embodiment, a composition isstable if the viscosity does not increase more than 150 percent over atime period of 30 days when stored at temperatures of 40° C. or less,more preferably 100 percent or less over a time period of 30 days andmost preferably 50 percent or less over a time period of 30 days.

Dihydrocarbyl hydroxylamines useful herein include any such compoundswhich when included in the compositions of this invention; improve thestability of the compositions as described herein. Preferreddihydrocarbyl amines correspond to the formula (R¹¹)₂ N—OH

wherein R¹¹ is independently in each occurrence a hydrocarbyl moiety.Preferably R¹³ is independently in each occurrence a C₂₋₃₀ alkyl,alkaryl or aryl moiety; more preferably a C₁₀₋₂₀ alkyl, alkaryl or arylmoiety; with C₁₀₋₂₀ alkyl moieties being even more preferred. Amongpreferred dihydrocarbyl hydroxylamines are hydroxylamine freebase fromBASF, hydroxylamine derivatives from Mitsui Chemicals America, Inc. andIrgastab FS Products from Ciba Specialty Chemicals which containsoxidized bis(hydrogenate tallow alkyl) amine also described asbis(N-dodecyl) N-hydroxylamine. The dihydrocarbyl hydroxylamines areutilized in sufficient amounts to stabilize the compositions of theinvention. Preferably the dihydrocarbyl hydroxylamines are used in anamount of about 1 parts per million of the compositions of the inventionor greater, more preferably about 2 parts per million or greater andmost preferably about 5 parts per million or greater. Preferably thedihydrocarbyl hydroxylamines are used in an amount of about 100,000parts per million of the compositions of the invention or less, morepreferably about 50,000 parts per million or less, even more preferablyabout 10,000 parts per million or less and most preferably about 3,000parts per million or less.

The compositions of the invention further comprise an accelerator forthe cure of the polymerizable compositions. The accelerators comprise atleast one compound containing a quinone structure or at least onecompound containing at least one aromatic ring and one or morepreferably two substituents, on the aromatic ring selected fromhydroxyl, ether and both when two substituents are used and they arelocated either ortho or para with respect to one another.

In one embodiment the accelerator is any compound containing a quinonestructure which compound accelerates the cure of the polymerizablecompositions. For adhesive compositions preferred quinones alsofacilitate adhesion of the polymeriazble compositions to substratesurfaces. Preferred quinone compounds contain the following structure:

Preferred classes of quinone compounds are substituted or unsubstitutedquinone, napthaquinone or anthraquinones. The substituent can be anysubstituent that does not interfere in the formation of free radicals orthe reaction of the free radicals with other compounds. Preferredquinone containing compounds correspond to one of the formulascontaining compound which corresponds to one of the structures:

wherein R⁸ is separately in each occurrence is any substituent whichdoes not prevent free radical formation or free radical reaction withother compounds; andd is separately in each occurrence an integer of from 0 to 4. Preferredquinone containing compounds are quinone compounds. Quinone compoundspreferably correspond to the formula:

Preferably, R⁸ is Separately in each occurrence R⁹, OR⁹ or SR⁹, whereinR⁹ is separately in each occurrence substituted or unsubstitutedhydrocarbyl; more preferably substituted or unsubstituted alkyl, aryl,aralkyl, even more preferably substituted or unsubstituted C₁₋₈₀ alkylC₆₋₆₀ aryl, C₆₋₉₀ aralkyl, and most preferably C₁₋₁₀ alkyl and C₆₋₁₄aryl. Preferably d is 0 to 2, even more preferably 0 to 1, and mostpreferably 0. Among preferred quinone structure containing compounds arebenzoquinone and ortho, meta, or para substituted benzoquinone and orthoand para quinone. Preferably R⁸ is R⁹ or OR⁹. More preferred quinonesinclude anthraquinone, benzoquinone, 2-phenylbenzoquinone, orthoquinoneand substituted benzoquinone. Most preferred quinones containingcompounds include benzoquinone.

The amount of quinone used is that amount which accelerates cure of thecompositions and does not inhibit adhesion of the composition to thesubstrate surface. If too little is used there is no significantincrease in cure speed. If too much is used and the composition will notadhere to a substrate surface. Preferably the quinone is used in anamount of about 0.01 percent by weight of the polymerizable compositionor greater, more preferably about 0.02 percent by weight or greater, andmost preferably about 0.04 percent by weight or greater. Preferably thequinone is used in an amount of about 0.1 percent by weight of thepolymerizable composition or less, more preferably about 0.8 percent byweight or less, and most preferably about 0.4 percent by weight or less.In a preferred embodiment, the quinone accelerator is present in anamount of about 0.1 percent to about 4.0 percent by weight of the resinpart of the composition.

In another embodiment the accelerator comprises at least one compoundcontaining at least one aromatic ring and at least one, preferably twosubstituents on the aromatic ring selected from hydroxyl, ether and bothwherein the two substituents are located either ortho or para withrespect to one another, hereinafter substituted aromatic ring containingcompound and a compound having a peroxy moiety. The substituted aromaticcompound can contain any aromatic moiety, including those with multiplering structures. The compounds preferably contain two or more functionalgroups selected from hydroxy and ether. Preferably the substitutedaromatic compounds contain at least one hydroxy and another hydroxy orether moiety. Most preferably the substituted aromatic compound containsat least one hydroxy and at least one ether moiety. Preferably thesubstituted compounds contain benzene, anthracene or napthalene aromaticring structures. The substituted aromatic compounds may be substitutedwith any substituent which does not interfere with the formation of freeradicals or the reaction of the free radicals with other compounds.Preferred substituents include alkyl, aryl, or aralkyl groups, andhetero atoms containing groups selected from the group comprising oxygenand sulfur. Most preferred substituents include aryl groups and heteroatom containing groups.

Preferably, the substituted aromatic compounds correspond to one of theformulas

whereinR¹⁰ is separately in each occurrence hydrogen or any substituent whichdoes not prevent free radical formation or free radical reaction withother compounds; andR⁸ and d are as previously defined. Preferably, R¹⁰ is separately ineach occurrence substituted or unsubstituted hydrocarbyl; morepreferably substituted or unsubstituted alkyl, aryl, aralkyl or aralkyl;even more preferably substituted or unsubstituted C₁₋₁₀₀ alkyl C₆₋₉₀aryl, or C₆₋₉₀ aralkyl and most preferably C₁₋₂₀ alkyl. e is 0 or 1,preferably 1.

More preferably the substituted aromatic containing compounds correspondto the formulas:

wherein R⁸, R¹⁰, d and e are described above.

Among most preferred substituted aromatic ring containing compounds areanthrahydroquinones, napthahydroquinones, methyl ether of hydroquinoneand alkylethers of hydroquinone. The amount of substituted aromatic ringcontaining compound used is that amount which accelerates cure of thecompositions, and which does not inhibit adhesion of the composition tothe substrate surface is used. If too little is used there is nosignificant increase in cure speed. If too much is used and thecomposition will not adhere to a substrate surface. Preferably thesubstituted aromatic ring containing compound is used in an amount ofabout 0.1 percent by weight of the polymerizable composition or greater,more preferably about 1 percent by weight or greater, and mostpreferably about 2 percent by weight or greater. Preferably thesubstituted aromatic ring-containing compound is used in an amount ofabout 4 percent by weight of the polymerizable composition or less, morepreferably about 3 percent by weight or less, and most preferably about2.5 percent by weight or less.

In conjunction with the substituted aromatic ring-containing compound aperoxy-containing compound is used. Any peroxy-containing compound thatreacts with the substituted aromatic ring-containing compound to formfree radicals may be used. Preferred peroxy-containing include dialkylperoxides, diaryl peroxides, diacyl peroxides, alkyl hydroperoxides,aryl hydroperoxides, and aryl hydroperoxides. More preferredperoxy-containing compounds include t-butyl peroxides, benzoyl peroxide,t-butyl perbenzoate. Most preferred peroxy-containing compounds includebenzoyl peroxide and t-butyl perbenzoate.

The amount of peroxy-containing containing compound used is that amountwhich accelerates cure of the compositions. If too little is used thereis no significant increase in cure speed. If too much is used theadhesive does not bond to polyolefins. Preferably the peroxy-containingcompound is used in an amount of about 0.1 percent by weight of thepolymerizable composition or greater, more preferably about 1 percent byweight or greater, and most preferably about 2 percent by weight orgreater. Preferably the peroxy-containing compound is used in an amountof about 4 percent by weight or less of the polymerizable composition,more preferably about 3 percent by weight or less, and most preferablyabout 2.5 percent by weight or less.

Preferably, the relative amount of peroxy containing compound tosubstituted aromatic ring containing compound is selected such that themajority of the resultant free radicals generated by the peroxy compoundreacts with the substituted aromatic ring compound. Thus, a molar ratioof peroxy containing compound to aromatic ring compound is one or less.If the ratio is too high then no adhesion to polyolefins would beobserved. If the ratio is too low then the adhesive cure rate is notincreased. Preferably the ratio amount of peroxy containing compound tosubstituted aromatic ring containing compound is about 1:4 or greater,and most preferably about 2:3 or greater. Preferably the ratio amount ofperoxy containing compound to substituted aromatic ring containingcompound is about 1:1 or less.

Preferably, the accelerator is located in the part that does not containthe organoboron compound. Often the part containing the organoboroncompound is referred to as the hardener side, and the other part isreferred to as the resin side because the largest part of thepolymerizable compound is found in this part. Hydrocarbyl as used hereinmeans any moiety having both carbon and hydrogen atoms and includessaturated and unsaturated, branched and unbranched, hydrocarbon chains.Alkyl refers to branched and unbranched saturated hydrocarbon chains.Alkenyl refers to branched and unbranched unsaturated hydrocarbonchains. Aryl means an aromatic hydrocarbon moiety. Alkaryl means anaromatic hydrocarbon moiety with a straight or branched hydrocarbonchain attached. Aralkyl means a straight or branched hydrocarbon chainwith an aryl group attached. Acyl means a hydrocarbyl and carbonylmoiety. Unless otherwise stated these moieties may be substituted withany other substituent which does not significantly interfere in thefunction of the compound to which the moiety is attached or bonded.

The two-part polymerizable compositions or adhesive compositions of theinvention are uniquely suited for use with conventional, commerciallyavailable dispensing equipment for two-part compositions. Once thetwo-parts have been combined, the composition should be used quickly, asthe useful pot life (open time) may be short depending upon the monomermix, the amount of complex, the amount of catalyst and the temperatureat which the bonding is performed. The adhesive compositions of theinvention are applied to one or both substrates and then the substratesare joined together, preferably with pressure to force excesscomposition out of the bond line. In general, the bonds should be madeshortly after the composition has been applied, preferably within about10 minutes. The typical bond line thickness is about 0.005 inches (0.13mm) to about 0.03 inches (0.76 mm). The bond line can be thicker if gapfilling is needed as the composition of the invention can function asboth an adhesive and a gap filler. The bonding process can easily becarried out at room temperature and to improve the degree of bonding itis desirable to keep the temperature below about 40° C., preferablybelow about 30° C., and most preferably below about 25° C.

The compositions may further comprise a variety of optional additives.One particularly useful additive is a thickener such as medium to high(about 10,000 to about 1,000,000) molecular weight polymethylmethacrylate which may be incorporated in an amount of about 10 to about60 weight percent, based on the total weight of the composition.Thickeners may be employed to increase the viscosity of the compositionto facilitate application of the composition.

Another particularly useful additive is an elastomeric material. Thematerials may improve the fracture toughness of compositions madetherewith which can be beneficial when, for example, bonding stiff, highyield strength materials such as metal substrates that do notmechanically absorb energy as easily as other materials, such asflexible polymeric substrates. Such additives can be incorporated in anamount of about 5 percent to about 35 percent by weight, based on thetotal weight of the composition. Useful elastomeric modifiers includechlorinated or chlorosulphonated polyethylenes such as HYPALON 30(commercially available from E.I. Dupont de Nemours & Co., Wilmington,Del.) and block copolymers of styrene and conjugated dienes(commercially available from Dexco Polymers under the Trademark VECTOR,and Firestone under the Trademark STEREON). Also useful, and even morepreferred, are certain graft copolymer resins such as particles thatcomprise rubber or rubber-like cores or networks that are surrounded byrelatively hard shells, these materials often being referred to as“core-shell” polymers. Most preferred are theacrylonitrile-butadiene-styrene graft copolymers available from Rohm andHaas. In addition to improving the fracture toughness of thecomposition, core-shell polymers can also impart enhanced spreading andflow properties to the uncured composition. These enhanced propertiesmay be manifested by a reduced tendency for the composition to leave anundesirable “string” upon dispensing from a syringe-type applicator, orsag or slump after having been applied to a vertical surface. Use ofmore than about 20 percent of a core-shell polymer additive is desirablefor achieving improved sag-slump resistance. Generally the amount oftoughening polymer used is that amount which gives the desired toughnessto the polymer or the adhesive prepared.

In some embodiments where a heterocyclic ring opening compound ispresent and is an oxirane, it may desirable to include some aziridinecontaining compound in the formulation as the aziridine enhances thestability of the formulation. Generally, enough aziridine is added toimprove the stability of the formulation. Preferably about 1 percent byweight or greater of aziridine based on the weight of the formulation isused and more preferably about 2 percent by weight or greater.Preferably about 10 percent by weight or less of aziridine based on theformulation weight is used and more preferably about 7 percent by weightor less is used.

Polymerizable compositions according to the invention may be used inwide variety of ways, including as adhesives, coatings, primers, tomodify the surface of polymers, and injection molding resins. They mayalso be used as matrix resins in conjunction with glass and metal fibermats such as in resin transfer molding operations. They may further beused as encapsulants and potting compounds such as in the manufacture ofelectrical components, printed circuit boards and the like. Quitedesirably, they provide polymerizable adhesive compositions that canbond a wide range of substrates, including polymers, wood, ceramics,concrete, glass and primed metals. Another desirable related applicationis their use in promoting adhesion of paints to low surface energysubstrates such as polyethylene, polypropylene,polyethyleneterephthalate, polyamides, and polytetrafluoroethylene, andtheir co-polymers. In this embodiment the composition is coated onto thesurface of the substrate to modify the surface to enhance the adhesionof the final coating to the surface of the substrate.

The compositions of the invention can be used in coating applications.In such applications the composition may further comprise a carrier suchas a solvent. The coating may further contain additives well known tothose skilled in the art for use coatings, such as pigments to color thecoating, inhibitors and UV stabilizers. The compositions may also beapplied as powder coatings and may contain the additives well known tothose skilled in the art for use in powder coatings.

The compositions of the invention can also be used to modify the surfaceof a polymeric molded part, extruded film or contoured object.Compositions of the invention can also be used to change thefunctionality of a polymer particle by surface grafting of polymerchains on to the unmodified plastic substrate.

Polymerizable compositions of the invention are especially useful foradhesively bonding low surface energy plastic or polymeric substratesthat historically have been very difficult to bond without usingcomplicated surface preparation techniques, priming, etc. By low surfaceenergy substrates is meant materials that have a surface energy of about45 mJ/m² or less, more preferably about 40 mJ/m² or less and mostpreferably about 35 mJ/m² or less. Included among such materials arepolyethylene, polypropylene, acrylonitrile-butadiene-styrene,polyamides, syndiotactic polystyrene, olefin containing blockco-polymers, and fluorinated polymers such as polytetrafluoroethlene(TEFLON) which has a surface energy of less than about 20 mJ/m². (Theexpression “surface energy” is often used synonymously with “criticalwetting tension” by others.) Other polymers of somewhat higher surfaceenergy that may be usefully bonded with the compositions of theinvention include polycarbonate, polymethylmethacrylate, andpolyvinylchloride.

The polymerizable compositions of the invention can be easily used astwo-part adhesives. The components of the polymerizable compositions areblended as would normally be done when working with such materials. Thedecomplexing agent for the organoboron compound is usually included withthe olefinic, polymerizable component so as to separate it from theorganoboron compound, thus providing one-part of the two-partcomposition. The organoboron compounds of the polymerization initiatorsystem provides the second part of the composition and is added to thefirst part shortly before it is desired to use the composition.Similarly, the Lewis acid catalyst where used for the heterocyclic ringopening compound polymerization is kept separate from the heterocyclicring opening compound. The Lewis acid catalyst may be added to the firstpart directly or it may be pre-dissolved in an appropriate carrier suchas a reactive olefinic monomer, i.e., methyl methacrylate or a MMA/PMMAviscous solution.

For a two-part adhesive such as those of the invention to be most easilyused in commercial and industrial environments, the volume ratio atwhich the two-parts are combined should be a convenient whole number.This facilitates application of the adhesive with conventional,commercially available dispensers. Such dispensers are shown in U.S.Pat. Nos. 4,538,920 and 5,082,147 (incorporated herein by reference) andare available from Conprotec, Inc. (Salem, N.J.) under the trade nameMIXPAC. Typically, these dispensers use a pair of tubular receptaclesarranged side-by-side with each tube being intended to receive one ofthe two-parts of the adhesive. Two plungers, one for each tube, aresimultaneously advanced (e.g., manually or by a hand-actuated ratchetingmechanism) to evacuate the contents of the tubes into a common, hollow,elongated mixing chamber that may also contain a static mixer tofacilitate blending of the two-parts. The blended adhesive is extrudedfrom the mixing chamber onto a substrate. Once the tubes have beenemptied, they can be replaced with fresh tubes and the applicationprocess continued. The ratio at which the two-parts of the adhesive arecombined is controlled by the diameter of the tubes. (Each plunger issized to be received within a tube of fixed diameter, and the plungersare advanced into the tubes at the same speed.) A single dispenser isoften intended for use with a variety of different two-part adhesivesand the plungers are sized to deliver the two-parts of the adhesive at aconvenient mix ratio. Some common mix ratios are 1:1, 2:1, 4:1 and 10:1,but preferably less than about 10:1 and more preferably less than about4:1.

Preferably, the mixed two-part compositions of the invention have asuitable viscosity to allow application without dripping. Preferably,the viscosities of the two individual components should be of the sameorder or magnitude. Preferably, the mixed compositions have theviscosity of about 100 (0.1 Pa·S) centipoise or greater, more preferablyabout 1,000 (1.0 Pa·S) centipoise or greater and most preferably about5,000 (5.0 Pa·S) centipoise or greater. Preferably the adhesivecompositions have a viscosity of about 150,000 (150 Pa·S) centipoise orless, more preferably about 100,000 (100 Pa·S) centipoise or less andmost preferably about 50,000 (50 Pa·S) centipoise or less.

SPECIFIC EMBODIMENTS

The following examples are included for illustrative purposes only andare not intended to limit the scope of the claims. Unless otherwisestated all parts and percentages are by weight.

Ingredients

The following ingredients were used in the examples providedhereinafter:

methyl methacrylate available from Rohm and Haas;

poly(methylmethacrylate) 350,000 mw available from Aldrich;

poly(methylmethacrylate) 996,000 mw available from Aldrich;

fumed silica available from Cabot Corporation under the trademark anddesignation

Cab-o-sil™ TS-720;

Acrylic acid available from Sigma Aldrich;

Hypalon™ 20 chlorosulfonated polyethylene available from Dupont-DowElastomers;

Scotchlite™ VS5500 glass bubbles available from 3M;

Methyl ether of hydroquinone available from Sigma Aldrich (MEHQ);

t-butyl peroxybenzoate available from Aztec Peroxides Inc.;

Methacrylic acid available from Sigma Aldrich;

Benzoquinone available from Aldrich; and

Complex of tri-n-butyl borane and methoxypropyl amine.

Two part formulations were prepared by mixing the ingredients for eachpart and then placed in separate containers. Several different part A(resin side) formulations were made.

Process for Preparing Resin Side Containing Benzoquinone as Accelerator

The following ingredients are added to a 1 gallon (3.79 liters) metalcan and rolled on a ball roll mill for 24 to 72 hours. The ingredientsare 150 grams of methyl methacrylate, 45 grams of polymethylmethacrylate (350,000 mw), 9 grams of polymethyl methacryalte (996,000mw) and 15 grams of chlorosulfonated polyethylene. 146 grams of theblended ingredients are added to an 8 oz. (236 mL) plastic cup to whichis added 33.99 grams or methyl methacrylate and 0.024 grams of methylether of hydroquinone. The ingredients are completely mixed by handusing a tongue depressor for 3 minutes. Four grams of glass bubbles and4 grams of fumed silica are added and the ingredients are completelymixed by hand using a tongue depressor for 3 minutes. Twenty four gramsof acrylic acid are added and the ingredients are completely mixed byhand using a tongue depressor for 3 minutes. Up to 0.096 grams orbenzoquinone are added and the ingredients are completely mixed by handusing a tongue depressor for 3 minutes. The resulting mixture ispackaged in an 8 oz. (236 mL) plastic cup.

Process for Preparing Resin Side Containing Methyl Ether of Hydroquinone

The following ingredients are added to a 1 gallon metal can and rolledon a ball roll mill for 24 to 72 hours. The ingredients are 150 grams ofmethyl methacrylate, 45 grams of polymethyl methacrylate (350,000 mw), 9grams of polymethyl methacrylate (996,000 mw) and 15 grams ofchlorosulfonated polyethylene. 146 grams of the blended ingredients areadded to a 8 oz. (236 mL) plastic cup to which is added 33.99 grams ofmethyl methacrylate and 4 grams of methyl ether of hydroquinone. Theingredients are completely mixed by hand using a tongue depressor for 3minutes.

Four grams of glass bubbles and 4 grams of fumed silica are added andthe ingredients are completely mixed by hand using a tongue depressorfor 3 minutes. Twenty eight grams of acrylic acid are added and theingredients are completely mixed by hand using a tongue depressor for 3minutes. Four grams of t-butyl peroxy-benzoate are added and theingredients are completely mixed by hand using a tongue depressor for 3minutes. The resulting mixture is packaged in an 8 oz. (236 mL) plasticcup.

Part B Hardener

Part B (hardener side) comprised 15 percent of a tri-n-butylborane-methoxy propyl amine complex, 8.0 percent of Jeffamine T403 amineterminated polyether polyol, 54 percent of methyl methacrylate, 15percent of poly(methylmethacrylate), 7 percent of poly(methylmethacrylate) polyacrylate copolymer and a stabilizer as listed below.

Several Part A formulations were prepared using the procedures describedabove. The formulations are described below in Table 1. TABLE 1 Example1 2 3 4 5 6 7 8 Ingredient (g) (g) (g) (g) (g) (g) (g) (g) Resin Blend200 200 50 50 50 50 50 50 Acrylic Acid 8 8 2 2 MEHQ 4 4 1 1 MethacrylicAcid 2 2 Methyl 3.5 3.5 3.497 Methacrylate Benzoquinone .024 t-butyl 4 400 00 00 00 00 00 peroxybenzoate Total 216 216 52 51 52 53.5 58.5 53.521

Adhesives as described above were tested for Lap shear strengthaccording to ASTM D3165-91 on the substrates listed below at severaltimes from application as listed below. The surface area covered andoverlapping was 1 inch (254 cm) wide by ½ inch (1.27 cm) long. The bondthickness of 30 mil (0.76 mm) was maintained using 30 mil (0.76 mm)glass beads. The samples were pulled on an Instron 5500 at a rate of 0.5inches (1.27 cm) per minute until failure and the stress at failure wererecorded in pounds per square inch. The results are compiled in Table 2below. The surfaces of the substrates were not pretreated. The sampleswere cured and tested at room temperature (about 23° C.). Thepolypropylene substrate was 30 percent glass filled polypropylene.Relative to the mode of failure: Cohesive failure means that the breakoccurred in the adhesive;

Adhesive failure means the adhesive pulled away from the substrate; andsubstrate means the substrate broke. TABLE 2 Cure time Failure StrengthExample Substrate hour Mode PSI (kPa) 1 Polypropylene 0.5 Cohesive 0  (0) 1 Polypropylene 1 Cohesive 15  (103) 1 Polypropylene 2 Adhesive359 (2475) 1 Polypropylene 3 Adhesive 678 (4675) 1 Polypropylene 5Substrate 829 (5716) 2 e-coat 0.5 Adhesive 2  (14) 2 e-coat 1 Adhesive11  (76) 2 e-coat 2 Cohesive 37  (255) 2 e-coat 3 Cohesive 237 (1634) 2e-coat 5 Cohesive 1082 (7460) 2 e-coat 24 Cohesive 2664 (18370)  2e-coat 24 Cohesive 2848 (19630)  2 e-coat 24 Cohesive 3253 (22420)  2e-coat 24 Cohesive 2598 (17910)  2 e-coat 24 Cohesive 2664 (18370)  2Polypropylene 24 Substrate 1170 (8066) 2 Polypropylene 24 Substrate 1172(8081) 2 Polypropylene 24 Substrate 1031 (7108) 2 Polypropylene 24Substrate 984 (6784) 2 Polypropylene 24 Substrate 1001 (6902) 3 e-coat.5 Cohesive 0   (0) 3 e-coat 1 Cohesive 4  (28) 3 e-coat 2 Cohesive 6 (41) 3 e-coat 3 Cohesive 18  (124) 3 e-coat 5 Cohesive 52  (359) 3e-coat 24 Cohesive 1936 (13350)  3 e-coat 24 Cohesive 1717 (11840)  3e-coat 24 Cohesive 1701 (11730)  3 Polypropylene 24 Substrate 930 (6412)3 Polypropylene 24 Substrate 1000 (6894) 3 Polypropylene 24 Substrate1004 (6922) 4 e-coat 0.5 Cohesive 5  (34) 4 e-coat 1 Cohesive 5  (34) 4e-coat 2 Cohesive 12  (83) 4 e-coat 3 Cohesive 26  (179) 4 e-coat 5Cohesive 164 (1130) 4 e-coat 24 Cohesive 2156 (14870)  4 e-coat 24Cohesive 2030 (14000)  4 e-coat 24 Cohesive 1338 (9225) 4 Polypropylene24 Substrate 1121 (7729) 4 Polypropylene 24 Substrate 825 (5688) 4Polypropylene 24 Substrate 971 (6695) 5 e-coat 0.5 Cohesive 3  (21) 5e-coat 1 Cohesive 5  (34) 5 e-coat 2 Cohesive 14  (97) 5 e-coat 3Cohesive 46  (317) 5 e-coat 5 Cohesive 120  (827) 5 e-coat 24 Cohesive1662 (11460)  5 e-coat 24 Cohesive 1828 (12600)  5 e-coat 24 Cohesive1571 (10830)  5 Polypropylene 24 Substrate 748 (5157) 5 Polypropylene 24Substrate 909 (6267) 5 Polypropylene 24 Substrate 806 (5557) 6 e-coat0.5 Cohesive 3  (21) 6 e-coat 1 Cohesive 7  (48) 6 e-coat 2 Cohesive 18 (124) 6 e-coat 3 Cohesive 38  (262) 6 e-coat 5 Cohesive 138  (951) 6e-coat 24 Cohesive 1748 (12050)  6 e-coat 24 Cohesive 1621 (11180)  6e-coat 24 Cohesive 1476 (10180)  6 Polypropylene 24 Substrate 1058(7226) 6 Polypropylene 24 Substrate 844 (5819) 6 Polypropylene 24Substrate 1049 (7233) 7 e-coat 0.5 Cohesive 2  (14) 7 e-coat 1 Cohesive6  (41) 7 e-coat 2 Cohesive 15  (103) 7 e-coat 3 Cohesive 40  (276) 7e-coat 5 Cohesive 198 (1365) 7 e-coat 24 Cohesive 1715 (11830)  7 e-coat24 Cohesive 1919 (13230)  7 e-coat 24 Cohesive 1952 (13460)  7Polypropylene 24 Substrate 980 (6757) 7 Polypropylene 24 Substrate 1013(6984) 7 Polypropylene 24 Substrate 1005 (6929) 8 e-coat 24 Cohesive2712 (18700)  8 e-coat 24 Cohesive 3349 (23090)  8 e-coat 24 Cohesive2339 (16130)  8 e-coat 24 Cohesive 2918 (20120)  8 e-coat 24 Cohesive3206 (22110)  8 Polypropylene 1 Adhesive 5  (34) 8 Polypropylene 2Adhesive 62  (427) 8 Polypropylene 3 Adhesive 713 (4916) 8 Polypropylene5 Substrate 721 (4971) 8 Polypropylene 24 Substrate 703 (4847) 8Polypropylene 24 Substrate 723 (4985) 8 Polypropylene 24 Substrate 746(5143) 8 Polypropylene 24 Substrate 751 (5478) 8 Polypropylene 24Substrate 721 (4971)

The examples illustrate the use of the oxidized bis(hydrogenated tallowalkyl) amines enhances the stability of other types of stabilizers. Thissituation is true whether used in a blend or alone.

1. A two part polymerizable composition comprising in one part anorganoboron compound capable of forming free radical generating speciesand in the second part one or more compounds capable of free radicalpolymerization and a cure accelerator greater than 1.0 percent by weightbased on the weight of the two part composition of at least one compoundcontaining at least one aromatic ring and one or more substituents onthe aromatic ring selected from hydroxyl, ether and both and a peroxidecontaining compound that reacts with the substituted aromatic ringcontaining compound to form free radicals.
 2. A two part compositionaccording to claim 1 wherein the second part further contains adecomplexing agent capable of decomplexing the organoboron compound uponcontacting the two parts. 3-4. (canceled)
 5. The composition of claim 1wherein the aromatic compound has two or more substituents of hydroxyl,ether or both wherein the substituents are located ortho or para to oneanother.
 6. The composition according to claim 1 wherein the organoboroncompound is an organoborate or an organoborane amine complex. 7-8.(canceled)
 9. A two part composition according to claim 4 wherein theaccelerator is a compound containing at least one aromatic ring and twosubstituents on the aromatic ring which comprises benzene ring, ananthracene or naphthalene with two substituents on the aromatic ringselected from hydroxyl, ether and both, wherein the two substituents arelocated either ortho or para with respect to one another and a peroxidecontaining compound.
 10. A two part composition according to claim 9wherein the compound containing at least one aromatic ring and one ormore substituents on the aromatic ring corresponds to one of theformulas:

wherein R⁸ is separately in each occurrence R⁹, —OR⁹ or —SR⁹; R⁹ isseparately in each occurrence is hydrocarbyl or substituted hydrocarbylwhich may be substituted with any substituent which does not preventfree radical formation or free radical reaction with other compounds;R¹⁰ is separately in each occurrence hydrogen or any substituent whichdoes not prevent free radical formation or free radical reaction withother compounds; d is separately in each occurrence an integer of from 0to 4 and e is separately in each occurrence 0 or
 1. 11. A two partcomposition according to claim 10 wherein the peroxide containingcompound is selected from the group of peroxides and hydroperoxides. 12.A two part composition according to claim 11 wherein the accelerator ispresent in an amount of from 1.0 percent to about 4 percent by weight ofthe two part composition and the peroxide containing compound is presentin an amount of about 0.5 percent to about 8 percent by weight based onthe weight of the two part composition. 13-14. (canceled)
 15. The twopart composition according to claim 1 wherein the organoboron compoundis an organoboron amine complex which comprises a trialkyl borane or analkyl cycloalkyl borane and the amine comprises a primary amine; asecondary amine; a polyamine having primary or secondary amines or both;ammonia; polyoxyalkylene amines; the reaction product of a diamine and adifunctional compound having groups which react with an amine, whereinthe reaction product has terminal amine groups; aryl amines;heterocyclic amines; a compound having an amidine structural component;aliphatic heterocycles having at least one secondary nitrogen in theheterocyclic ring wherein the heterocyclic compound may also contain oneor more additional secondary or tertiary nitrogen atoms, oxygen atoms,sulfur atoms, or double bonds in the heterocycle; alicyclic compoundshaving bound to the alicyclic ring one or more substituents containingan amine groups; conjugated imines; or mixtures thereof. 16-24.(canceled)
 25. A two part polymerizable composition comprising in onepart an organoboron compound capable of forming free radical generatingspecies wherein the organoboron compound is an organoborate and in thesecond part one or more compounds capable of free radical polymerizationand a cure accelerator comprising a) greater than about 0.01 percent byweight of the two part composition of at least one compound containing aquinone structure or b) greater than 1.0 percent by weight based on theweight of the two part composition of at least one compound containingat least one aromatic ring and one or more substitutents on the aromaticring selected from hydroxyl, ether and both and a peroxide containingcompound that reacts with the substituted aromatic ring containingcompound to form free radicals.
 26. A two part composition according toclaim 25 wherein the second part further contains a decomplexing agentcapable of decomplexing the organoboron compound upon contacting the twoparts.
 27. The composition of claim 25 wherein the aromatic compound hastwo or more substituents of hydroxyl, ether or both wherein thesubstituents are located ortho or para to one another.
 28. A two partcomposition according to claim 26 wherein the accelerator is asubstituted or unsubstituted quinone, napthaquinone or anthraquinone.29. A two part composition according to claim 28 wherein the acceleratoris a quinone containing compound which corresponds to one of thestructures:

wherein R⁸ is separately in each occurrence is OR⁹, SR⁹ or R⁹; R isseparately in each occurrence a substituted or unsubstituted hydrocarbylwhich may be substituted with any substituent which does not preventfree radical formation or free radical reaction with other compounds;and d is separately in each occurrence an integer of from 0 to
 4. 30. Atwo part composition according to claim 25 wherein the accelerator is acompound containing at least one aromatic ring and two substituents onthe aromatic ring which comprises benzene ring, an anthracene ornaphthalene with two substituents on the aromatic ring selected fromhydroxyl, ether and both, wherein the two substituents are locatedeither ortho or para with respect to one another and a peroxidecontaining compound.
 31. A two part composition according to claim 30wherein the compound containing at least one aromatic ring and one ormore substituents on the aromatic ring corresponds to one of theformulas:

wherein R⁸ is separately in each occurrence R⁹, —OR⁹ or —SR⁹; R⁹ isseparately in each occurrence is hydrocarbyl or substituted hydrocarbylwhich may be substituted with any substituent which does not preventfree radical formation or free radical reaction with other compounds;R¹⁰ is separately in each occurrence hydrogen or any substituent whichdoes not prevent free radical formation or free radical reaction withother compounds; d is separately in each occurrence an integer of from 0to 4 and e is separately in each occurrence 0 or
 1. 32. A two partcomposition according to claim 31 wherein the peroxide containingcompound is selected from the group of peroxides and hydroperoxides. 33.A two part composition according to claim 32 wherein the accelerator ispresent in an amount of from 1.0 percent to about 4 percent by weight ofthe two part composition and the peroxide containing compound is presentin an amount of about 0.5 percent to about 8 percent by weight based onthe weight of the two part composition.
 34. A two part compositionaccording to claim 28 wherein the accelerator is present in an amount offrom about 0.1 percent to about 4.0 percent by weight of the resin partcomposition.